This invention pertains to a sash lock for a pivotally mounted window and, more particularly, for a casement window. The sash lock is of a new and improved construction providing an effectively sealed transition between the interior and exterior of the case of the sash lock by means of an operating member which is exposed externally of the case and extends within the interior of the case and carries a movable lock member for coaction with a keeper. The exposed part of the operating member is shaped to remain in sealing relation with an opening in the top of the case.
A prior sash lock for a casement window is shown in Van Klompenburg U.S. Pat. No. 4,059,298, owned by the assignee of this application. In the prior sash lock, a generally planar operating member carries a lock member positioned within the case of the sash lock for coaction with a keeper and a portion of the generally planar operating member extends through an elongate opening defined by vertically-spaced walls of a section of the case and mounts a handle which can move along the length of the elongate opening between two operative positions in which the sash lock is either in lock or unlocked positions.
In the prior sash lock, there is a vertical wall with an opening in which a generally circular part of the planar operating member is disposed and a pair of vertical edges at the sides of the opening lie closely adjacent to the periphery of the circular part of the planar member in an effort to seal this opening between the interior and exterior of the sash lock case. Additionally, there is a disc-shaped spring fitted on the pivot mounting for the operating member positioned between the underside of the case top wall and the upper surface of the circular part of the planar operating member to hold the planar operating member in adjusted position and also to further effect a seal between the interior and exterior of the case. This prior sash lock has not effectively precluded passage of insects from the interior of the case to the exterior thereof.
A modification of the prior sash lock is a nonhanded unit, in that it can be associated with either a right-hand or left-hand casement window by having two different lock positions wherein a lock member is associated with a keeper. This modification having two lock positions is shown in Anderson U.S. Pat. No. 4,429,910, also owned by the assignee of this application.
This last-mentioned patent discloses a structure wherein a bug entry problem does not arise since the handle is associated with a rotatable shaft passing through a circular opening in the top of the sash lock case and which has only rotational movement within the opening and can be effectively sealed.
The sash lock embodying the invention provides for effective sealing of an operating member of the sash lock which is positioned partly within the case and partly exteriorly thereof, without requiring extremely close tolerances between parts of the operating member and the case and a handle may be directly associated with the exposed part of the operating member.